TOKYO/SINGAPORE, Feb 21 (Reuters) - Japan's Mitsubishi Corp 8058.T bought a naphtha cargo from Iran last month, the Asian country's first such purchase from Iran since October 2016, sources familiar with the matter said.

The naphtha cargo, loaded in late January, has arrived in Japan and is from the new Persian Gulf Star Refinery (PGSR), one source added.

The cargo contains high sulphur, restricting the number of petrochemical makers that can use it.

The sources declined to be named as they are not authorised to speak to the media.

A Mitsubishi spokesman confirmed it had bought naphtha from Iran recently, but declined to comment on details or which refinery the cargo was from due to company policy.

Japan's customs-cleared trade data, which started in 1988, showed Japan last imported a naphtha cargo from Iran in October.

January data is not available until Feb. 24.

PGSR has a condensate splitter but traders say it is only making sporadic offers now as its secondary units are not ready.

Once its secondary units are commissioned this year, the refinery will cease naphtha exports as the fuel will be channelled to the gasoline pool.

(Reporting by Osamu Tsukimori in TOKYO and Seng Li Peng in SINGAPORE; Editing by MarkPotter) ((osamu.tsukimori@thomsonreuters.com, +813 6441 1857, Reuters Messaging: osamu.tsukimori.thomsonreuters.com@reuters.net;))